Propeller



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PROPELLER.

APPLICATION man we. 5. 1920.

Patented Jan. '25, 1921.

UNITED STATES HENRY FREDERICK RAE, or CUMBRAE, ENGLAND.

PROPELLER.

Specification of Letters Patent. Patented Jan, 25, 1921 Application filed January 5, 1920. Serial No. 349,503.

To all w 7mm it may concern:

Be it known that I, HENRY Fnnnnnron Ran, a subject of the King of Great Britain and Ireland,- and residing at Cumbrae, Parrock avenue, Gravesend, in. the county of Kent, England, have invented new and useful improvement in Propellers of which the fol lowing is a specification.

This invention relates to looped blade screw propellers and is designed with the object of making a propeller from ductile metal and obtaining greater speed or power therefrom for driving craft provided therewith without slip through either air or water, with fewer revolutions per minute and with a smaller consumption of fuel as compared with propellers in ordinary use.

The invention consists essentially in the construction of a propeller cut from a duetile disk-like metal shape that decreases in thickness outwardly from the center, the said propeller being pierced at the forward central part for securing on a propeller shaft and having blades with peripheral extensions each bent inwardly rearward to form the correct pitch and secured at right angles to the propeller shaft rearward of the said forward central part.

Examples of propellers constructed in ac cordance with this invention are illustrated in the accompanying drawings of which Figure 1 is a central sectional view through the disk'like blank from which such propellers are cut.

Fig. 2 is a front or rear view of the blank and showing the lines along which it is cut to form a two or four bladed propeller, and

Fig. 3 is a side view of a two-bladed propeller made from a blank such as shown in Figs. 1 and 2 and mounted on a propeller shaft end.

Fig. i is a view similar to Fig. 2 of a blank cut to form another type of the two-bladed propeller.

Fig. 5 is a view, also similar to Fig. 2, but cut to form a three bladed propeller and Fig. 6 is a rear view of a propeller formed from the blank shownin Fig. 5.

Referring first to the form of propeller shown in Figs. 1, 2 and 3, the ductile disklike blank within the broken lines Fig. 2 is indicated by a and is shown in Fig. 1 as decreasing in thickness from the central shaft bore 5 to the periphery where it is thinnest and from it are cut the two blades 0, c; or, two additional blades d, 03 occupying the space inclosed by dotted lines between the blades 0, c may be cut from the blank (4 to make a four bladed propeller. Each blade is provided with an extreme portion 6, e perforated as at 7', 7 and when these blades are to be completed the portions 6, e are bent rearwardly inward to the center so that the holes 7", 7" may be passed on the propeller shaftend at right angles with the tips 6, e.

The propeller shaft g is screwed at h and the propeller is correspondingly screwed in its bore 2) to engage the shaftpart h. Lefthand screws for the propeller which tend to screw forwardly, and so tighten, are shown, but on a shaft for a left-hand propeller a right-hand screw is employed.

In mounting the propeller the nut i is screwed on the part it tightly against the propeller at b so as to lock it against the adjacent shaft-shoulder while the blade extremities e, c are screwed to the shaft extremity by jamming them between a shoulder near the end of the shaft 9 and a nut j and both the nuts 2' and j are locked in place by means of the pins 70, it; any distance re maining between a nut and a pin being occupied by washers of suitable thickness.

Instead of cutting two or four relatively narrow blades as shown in Fig. 2 a pair of relatively wide blades may be cut from the blank, as indicated in F ig. 4. Here the blades and extremities utilize nearly the whole of the blank instead of only about half as in the case of the two bladed propeller of Fig. 2.

The blank in Fig. 5 is shown as divided into three blades and it will be obvious that according to this invention a five or a six bladed propeller may equally well be out. In practice the two last mentioned forms are found to be well suited for air moving ventilation purposes.

The relatively small diameter of the propeller as compared with that of the disk like blank is shown by both Figs. 3 and 6. The forward borders Z, Z are the cutting or entering edges and these pick up the water or air and so enable the blades to draw or thrust the fluid rearward toward the propeller center.

I claim:

1. A. looped screw propeller formed from a disk-like plate decreasing in thickness from the center outward and having blades joined integrally one end by a radial part adapt" ed for fixing on a propeller shaft and blade tips extending toward and adapted for fixing on the end of the propeller shaft at right angles therewith; in combination with a propeller shaft for carrying said propeller and by means of which it may be operated and means for fixing said propeller in place on said shaft substantially as described.

2. A looped screw propeller having in combination, propeller blades cut and bent from a disk-like plate that decreases in thickness from the center outwardly, that are joined integrally at their fore ends by. a

, peller shaft screwed and drilled for carrying said propeller and nuts and pins for securing said propeller and said shaft together, substantially as described. 7

HENRY FREDERICK RAE. 

